CompuServe Messages

Christopher, I think that I have a pretty good understanding of what V.32 and V.42 as well as the difference between v.42 and v.42bis (also the proposed v.32bis). As you stated V.32 is a hardware spec similar to Bell 212 or V.22 while V.42 is simple a protocal such as MNP. You can have a modem use any form of hardware handshaking and still have the V.42 error correction and data compression on top of it and thus call it a V.42 modem. Hayes makes a modem call the Hayes SmartModem 9600 V series which uses Hayes propriatary ping-pong protocal as the hardware spec and V.42 as the error checking. V.32 is a spec for 9600 full-duplex and does not include having any error checking or data compression, so it is advantagous to have the v.42 (or better yet v.42bis) error checking on top of the v.32 hardware. The v.42 standard calls for its own form of error checking and will fall back to MNP level 3, if the other side of the connection only supports MNP. The V.42bis adds data compression which is not in either MNP 3, or V.42. Now, what I said in the last article is that the modem which advertised itself as v.42 automatically had MNP level 3 as that is built into the v.42 standard. Also I warned that just because the modem advertised v.42 didn't mean it used a standard hardware spec such as v.32 or v.22, as a result even though it has v.42 it will still only be able to communicate with modems using the same hardware spec, which in the case of Hayes means only other Hayes V series. -Jason-